expression
anyone can make a mistake; even experts slip up
Proverb literally meaning 'even Kōbō Daishi's brush makes mistakes,' used to console someone who has made an error by noting that even the greatest masters are not perfect.
失敗しても気にしないで。弘法にも筆の誤りというから。
Don't worry about the mistake. As they say, even Homer sometimes nods.
Both are proverbs meaning 'even experts make mistakes.' 弘法にも筆の誤り specifically references a master calligrapher, while 猿も木から落ちる uses a monkey falling from a tree as a metaphor.
A proverb attributed to the famous Heian-period Buddhist monk and calligrapher Kōbō Daishi (Kūkai), suggesting that even his brushwork could contain errors.